Estimate cement, sand, aggregate, and water for standard nominal concrete mixes. Brand-styled, field-ready, and editable parameters.
Leave blank to use grade default.
Typical 1.50–1.57; default 1.54.
Extra allowance for spillage, etc.
Default 50 kg per bag.
Free surface moisture in fine aggregate.
Free surface moisture in coarse aggregate.
How to Calculate Concrete for Nominal Mix (M5–M25)
Nominal mix concrete is prepared using fixed volumetric ratios of cement, sand, and coarse aggregate. It is commonly used up to grade M25 for general construction works. Below is a practical method for estimating quantities of cement, sand, aggregate, and water for any nominal grade, along with key tips and worked examples.
Step 1: Know the Mix Ratios
Standard nominal mix ratios are defined in IS 456 for grades up to M25: M5 (1:5:10), M7.5 (1:4:8), M10 (1:3:6), M15 (1:2:4), M20 (1:1.5:3), M25 (1:1:2). These ratios indicate cement : sand : aggregate parts by volume.
Step 2: Convert Wet Volume to Dry Volume
Multiply the target wet volume by a dry volume factor (typically 1.50–1.57; use 1.54 as default) and add a small wastage allowance (2–5%). This accounts for voids and bulking of sand.
Step 3: Split Volume by Mix Parts
Divide the dry volume into cement, sand, and aggregate volumes using the ratio parts. For example, in M20 (1:1.5:3), the total parts = 5.5. Cement = (1/5.5) × Dry Volume, Sand = (1.5/5.5) × Dry Volume, Aggregate = (3/5.5) × Dry Volume.
Step 4: Convert Volumes to Mass
Multiply volumes by material bulk densities (cement ≈ 1440 kg/m³, sand ≈ 1600 kg/m³, aggregate ≈ 1500 kg/m³). Cement mass can be divided by 50 to get the number of bags.
Step 5: Calculate Water Requirement
Water is computed using the water–cement ratio. For example, if w/c = 0.5 and cement = 400 kg, then water = 0.5 × 400 = 200 liters. Adjust for moisture in aggregates if necessary.
Worked Example (M20): For 1 m³ wet volume, Dry Volume = 1 × 1.54 × 1.02 = 1.57 m³. Parts = 5.5. Cement = 0.286 m³ × 1440 = 412 kg (≈ 8.2 bags). Sand = 0.429 m³ × 1600 = 686 kg. Aggregate = 0.857 m³ × 1500 = 1286 kg. Water = 0.5 × 412 = 206 L.
Conversion Tips
- 1 m³ = 35.315 ft³
- 1 m³ = 1.308 yd³
- Order in the unit your supplier provides (m³, ft³, or yd³).
Common Mistakes to Avoid
- Using nominal mixes above M25 (design mix required).
- Mixing metric and imperial units.
- Not accounting for wastage or aggregate moisture.
In summary: select grade and ratio, calculate dry volume, split into parts, convert to mass, and apply water–cement ratio. The calculator automates this process, minimizes errors, and ensures accurate material estimation for site use.